Ultrasound is sound with frequencies greater than 20 kilohertz. This frequency is the approximate upper audible limit of human hearing in healthy young adults. The physical principles of acoustic waves apply to any frequency range, including ultrasound. Ultrasonic devices operate with frequencies from 20 kHz up to several gigahertz.
Medical ultrasound includes diagnostic techniques using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics or to generate an informative audible sound. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography, or echography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. The machine used is called an ultrasound machine, a sonograph or an echograph. The visual image formed using this technique is called an ultrasonogram, a sonogram or an echogram.
Elastography is any of a class of medical imaging modalities that map the elastic properties and stiffness of soft tissue. The main idea is that whether the tissue is hard or soft will give diagnostic information about the presence or status of disease. For example, cancerous tumours will often be harder than the surrounding tissue, and diseased livers are stiffer than healthy ones.
The Pratt School of Engineering is located at Duke University in the United States. The school's associated research, education, alumni and service-to-society efforts are collectively known as Duke Engineering.
Contrast-enhanced ultrasound (CEUS) is the application of ultrasound contrast medium to traditional medical sonography. Ultrasound contrast agents rely on the different ways in which sound waves are reflected from interfaces between substances. This may be the surface of a small air bubble or a more complex structure. Commercially available contrast media are gas-filled microbubbles that are administered intravenously to the systemic circulation. Microbubbles have a high degree of echogenicity. There is a great difference in echogenicity between the gas in the microbubbles and the soft tissue surroundings of the body. Thus, ultrasonic imaging using microbubble contrast agents enhances the ultrasound backscatter, (reflection) of the ultrasound waves, to produce a sonogram with increased contrast due to the high echogenicity difference. Contrast-enhanced ultrasound can be used to image blood perfusion in organs, measure blood flow rate in the heart and other organs, and for other applications.
Ronald H. Silverman is an American ophthalmologist. He is currently Professor of Ophthalmic Science at Columbia University Medical Center. He is currently the director of the CUMC Basic Science Course in Ophthalmology, which takes place every January at the Harkness Eye Institute. He departed Weill Cornell Medical College in 2010, where he was Professor of Ophthalmology as well as a Dyson Scholar and the Research Director of the Bioacoustic Research Facility, Margaret M. Dyson Vision Research Institute at Weill Cornell.
Floyd Dunn was an American electrical engineer who made contributions to all aspects of the interaction of ultrasound and biological media. Dunn was a member of Scientific Committee 66 of the National Council on Radiation Protection and Measurements as well as many FDA, NIH, AIUM, and ASA committees. He collaborated with scientists in the UK, Japan, China and Post-Soviet states.
Thermoacoustic imaging was originally proposed by Theodore Bowen in 1981 as a strategy for studying the absorption properties of human tissue using virtually any kind of electromagnetic radiation. But Alexander Graham Bell first reported the physical principle upon which thermoacoustic imaging is based a century earlier. He observed that audible sound could be created by illuminating an intermittent beam of sunlight onto a rubber sheet. Shortly after Bowen's work was published, other researchers proposed methodology for thermoacoustic imaging using microwaves. In 1994 researchers used an infrared laser to produce the first thermoacoustic images of near-infrared optical absorption in a tissue-mimicking phantom, albeit in two dimensions (2D). In 1995 other researchers formulated a general reconstruction algorithm by which 2D thermoacoustic images could be computed from their "projections," i.e. thermoacoustic computed tomography (TCT). By 1998 researchers at Indiana University Medical Center extended TCT to 3D and employed pulsed microwaves to produce the first fully three-dimensional (3D) thermoacoustic images of biologic tissue [an excised lamb kidney ]. The following year they created the first fully 3D thermoacoustic images of cancer in the human breast, again using pulsed microwaves. Since that time, thermoacoustic imaging has gained widespread popularity in research institutions worldwide. As of 2008, three companies were developing commercial thermoacoustic imaging systems – Seno Medical, Endra, Inc. and OptoSonics, Inc.
Sonoporation, or cellular sonication, is the use of sound in the ultrasonic range for increasing the permeability of the cell plasma membrane. This technique is usually used in molecular biology and non-viral gene therapy in order to allow uptake of large molecules such as DNA into the cell, in a cell disruption process called transfection or transformation. Sonoporation employs the acoustic cavitation of microbubbles to enhance delivery of these large molecules. The exact mechanism of sonoporation-mediated membrane translocation remains unclear, with a few different hypotheses currently being explored.
Acoustic radiation force (ARF) is a physical phenomenon resulting from the interaction of an acoustic wave with an obstacle placed along its path. Generally, the force exerted on the obstacle is evaluated by integrating the acoustic radiation pressure over its time-varying surface.
Mathias Fink, born in 1945 in Grenoble, is a French physicist, professor at ESPCI Paris and member of the French Academy of Sciences.
The IEEE Biomedical Engineering Award is a Technical Field Award of the IEEE given annually for outstanding contributions to the field of biomedical engineering. It was established in 2010.
Nadine Barrie Smith (1962–2010) was an American biomedical researcher in the field of therapeutic ultrasound and non-invasive drug delivery. She was also an educator and mentor, especially to women students.
Synthetic aperture ultrasound (SAU) imaging is an advanced form of imaging technology used to form high-resolution images in biomedical ultrasound systems. Ultrasound imaging has become an important and popular medical imaging method, as it is safer and more economical than computer tomography (CT) and magnetic resonance imaging (MRI).
Eleanor Phoebe Jane Stride is a Professor of Biomaterials at St Catherine's College, Oxford. Stride engineers drug delivery systems using carefully designed microbubbles and studies how they can be used in diagnostics.
Muyinatu "Bisi" A. Lediju Bell is a researcher and faculty member. She is the John C. Malone Associate Professor of Biomedical Engineering, Electrical and Computer Engineering, and Computer Science at Johns Hopkins University. She is also the director of the Photoacoustic and Ultrasonic Systems Engineering Laboratory.
James (Jim) Gegan Miller is an American physicist, engineer, and inventor whose primary interests center around biomedical physics. He is currently a professor of physics, Medicine, and Biomedical Engineering, emeritus, at Washington University in St. Louis, where he holds the Albert Gordon Hill Endowed Chair in the Faculty of Arts and Sciences. He is notable for his interdisciplinary contributions to biomedical physics, echocardiography, and ultrasonics.
Katherine Whittaker Ferrara is an American engineer who is a professor of radiology at Stanford University. Ferrara has been elected a Fellow of the American Association for the Advancement of Science, Institute of Electrical and Electronics Engineers and American Institute for Medical and Biological Engineering.
Melissa Louise Mather is an Australian physicist who is Professor in Biological Sensing and Imaging at the University of Nottingham. Her research considers the development of novel sensing techniques, including ultrasound, single molecule imaging and nitrogen-vacancy centers in diamond.
Gregg E. Trahey is an American biomedical engineer and academic in the field of medical ultrasound. He is the Robert Plonsey Distinguished Professor of Biomedical Engineering at Duke University. In 2022, he was named a fellow of the Institute of Electrical and Electronics Engineers (IEEE) "for contributions to speckle tracking and acoustic radiation force impulse imaging in medical ultrasound".
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